DE102022113447A1 - Device, mobile device, system and method for storing a private data record and method for carrying out a transaction - Google Patents

Abstract

The invention relates to a method for storing a private data set, the method comprising the steps: establishing a contactless communication connection between a device and a mobile device, the device comprising a memory; creating the private record; transmitting the private data set from the mobile device to the device; and storing the private data set in the device's memory.

Description

Technical area

The invention relates to a method and a system for storing a private data set. The invention further relates to a device and a mobile device for storing a private data record. The invention also relates to a method for carrying out a transaction using the private data record.

Technical background

Cryptocurrencies, e.g. Bitcoin, Ethereum and many others, are based on a decentralized database. The database is usually based on a blockchain. All cryptocurrency transactions are documented in the database. To ensure that cryptocurrency transactions are carried out by the owner, cryptographic methods are used. In particular, asymmetric cryptographic techniques are used.

A cryptocurrency transaction usually requires a private key and a public key. Transactions can be sent to addresses that can be derived from the public keys. For example, the address is a hash value of a public key. Through the private (non-public) key, a user can access cryptocurrency of an address. To make the handling of private keys easier, seed phrases (also called seeds) can be used. These can be a series of words. Private keys can be derived based on the seed phrases.

Access to cryptocurrency is linked to the private key or seed phrase. In other words, whoever owns the private key or seed phrase can control the cryptocurrency. Therefore, secure storage of private keys or seed phrases is essential.

In order to avoid losing the private key or seed phrase, users usually store it in one place, e.g. written down on paper. Storing sensitive data is not trivial. The data should be stored securely, but at the same time the data should be easy and user-friendly to access.

Creating a pair of a private key or seed phrase and a public key also poses a security risk. The pair is often created by a service provider, for example a web service, and the service provider makes the pair available to a user. On the one hand, a dubious service provider can store the pair or at least the private key or seed phrase after it has been made available to the user. In this case, the service provider has full access to the cryptocurrency of the user who uses the provided pair for transactions. Likewise, the created pair can be “intercepted” by a third party when transmitted to the user, so that the third party has access to the user’s cryptocurrency.

Summary of Revelation

One object of the invention is to enable secure and user-friendly storage of private data (e.g. private keys and/or seed phrases). A further object of the invention is to enable creation of private data with increased security. A still further object of the invention is to simplify handling of private data. A still further object of the invention is to enable cost-effective storage of private data.

At least one of the tasks is solved by the combination of features of the independent claims. Embodiments are defined in the dependent claims.

Disclosed is a method for storing and/or retaining a private data set. The method includes establishing a contactless communication connection between a device and a mobile device. The device includes a memory. The method includes creating the private record, transmitting the private record from the mobile device to or to the device, and storing the private record in the memory of the device.

By transmitting the private data set from the mobile device to the device, a user can control and/or verify the transmission to the device. The device with the stored private data set can be stored securely by the user. If the user needs the private record for a transaction, a contactless communication link can be established between the mobile device and the device and the private record can be transmitted from the device to the mobile device.

After transmitting the private data set from the mobile device to the device or to the device, the contactless communication connection can be terminated or aborted. Likewise, the contactless communication connection between the mobile device and the device can be terminated or aborted after the private data set has been stored in the memory.

There cannot be a private record stored in the device before the private record is created. Alternatively or additionally, no private data set may be stored in the device prior to transferring the private data set from the mobile device to the device. Alternatively or additionally, prior to storing the private data set in the memory of the device, no (other) private data set may be stored in the device.

The private data set is preferably created or created or generated by the mobile device.

The private record may be a record for a cryptographic operation. In particular, the private record is a private record for an asymmetric cryptographic operation. The private record can be a string. The character string can contain letters and/or numbers.

The contactless communication link can also be referred to as a wireless communication link. With a contactless communication connection, there need not be any direct or indirect (physical) contact between the mobile device and the device. Nevertheless, data can be exchanged between the mobile device and the device via the wireless communication link. For example, the mobile device may transmit data to the device via the wireless communication link and/or the device may transmit data to the mobile device via the wireless communication link. Data can be transmitted using electromagnetic waves via the contactless communication connection.

The contactless communication connection can be a secured contactless communication connection. For example, a secure communication channel can be established between the device and the mobile device. Data can be transmitted in encrypted form via the contactless communication connection. The device and the mobile device can communicate with each other in a cryptographically secured manner via the contactless communication connection. The contactless communication connection can be a cryptographically secured contactless communication connection.

The device may include an antenna. In particular, the device includes a near field communication connection antenna.

The device may include a processor. The processor can be set up to control and/or carry out operations of the device.

The device may include an NFC chip. NFC is an abbreviation for near field communication. The NFC chip may include the processor and memory. The NFC chip may be connected to an NFC antenna or may include the NFC antenna.

The memory of the device may be non-volatile memory. The memory may have a storage capacity of less than 5 MB, preferably less than 3 MB, more preferably less than 1.5 MB, more preferably less than 600 kB, more preferably less than 300 kB, more preferably less than 200 kB, more preferably less than 50 kB, more preferably less than 1.0 kB, more preferably less than 500 B (bytes), more preferably less than 200 B.

The processor, memory, and/or antenna may be completely embedded in the device or completely surrounded by the device.

The device can be a card. In particular, the device is a chip card, a key card, a smart card or an integrated circuit card (ICC). The dimensions of the device can correspond to the card dimensions according to ISO 7816, for example ID-1. The device can have a credit card format.

The device may comprise plastic. The device can essentially consist of plastic, i.e. apart from electronic components. Alternatively or additionally, the device may comprise metal. The device can consist essentially of metal.

The mobile device can be a mobile device. In particular, the mobile device is a smartphone, a smartwatch, a wearable device or a tablet. The mobile device can be a user mobile device, i.e. the mobile device can be a user's device. The mobile device can be portable.

The mobile device may include an application (app). The application can be used to establish and/or terminate the contactless communication connection. The application can control data exchange between the device and the mobile device. For example The application can enable the contactless communication connection to be established and/or terminated by user input. Alternatively or additionally, the application may enable the private data set to be transmitted from the mobile device to the device or to the device upon user input. Alternatively or additionally, the application may allow the private data set to be stored in the device following user input. Alternatively or additionally, the application may enable the private data set to be transmitted from the device to the mobile device following user input. The application can create or generate the private data set independently of third parties.

The mobile device may include a display. Prompts to the user can be shown on the display. Alternatively or additionally, input fields for the user can be shown on the display. The user can control the operation of the mobile device through one or more inputs. For example, the user can enter data in one or more input fields. Alternatively or additionally, the user can select one or more selection fields. The selection fields can be shown on the display.

The display may be a touch display (also known as a touch-sensitive display). A user can make entries into the mobile device via the touch display.

The contactless communication connection may be a near field communication (NFC) connection. The contactless communication connection cannot be established if a distance between the device and the mobile device is greater than 0.50 m. In particular, the contactless communication connection cannot be established if a distance between the device and the mobile device is greater than 0.40 m, preferably greater than 0.30 m, more preferably greater than 0.20 m, more preferably greater than 0.15 m, more preferably greater than 0.10 m.

If a distance between the device and the mobile device is greater than 0.50 m, preferably greater than 0.40 m, more preferably greater than 0.30 m, more preferably greater than 0.20 m, more preferably greater than 0.15 m, more preferably greater than 0.10 m, the contactless communication connection cannot be established.

The contactless communication connection can be based on RFID technology. The contactless communication link can be an RFID communication link. RFID is an abbreviation for identification using electromagnetic waves (radiofrequency identification).

The contactless communication link may use or communicate at a frequency between 13.00 MHz and 14.00 MHz, in particular at substantially (± 2% or ± 1%) 13.56 MHz. Communication and/or data exchange between the device and the mobile device can take place at a frequency between 13.00 MHz and 14.00 MHz, in particular at essentially (± 2% or ± 1%) 13.56 MHz.

The maximum data transfer rate between the device and the mobile device can be a maximum of 5.0 Mbit/s. In particular, the maximum data transfer rate between the device and the mobile device is at most 3.0 Mbit/s, preferably at most 2.0 Mbit/s, more preferably at most 1.0 Mbit/s, more preferably at most 0.8 Mbit/s, more preferably at most 0, 6 MBit/s, more preferably at most 0.5 MBit/s. The maximum data transfer rate between the device and the mobile device may refer to the maximum data transfer rate over the contactless communication link. The maximum data transfer rate may be the maximum data transfer rate over the contactless communication link.

In particular, the contactless communication connection is not a Bluetooth connection and/or a WLAN connection.

The contactless communication link may conform to or be based on at least one of the following standards: ISO 14443, ISO 18092, ISO 21481 ECMA 340, ECMA 352, ECMA 356, ECMA 362 and ETSI TS 102 190. Generally, standards disclosed herein may be and standards refer to the version valid on the filing date.

Data can be exchanged via electromagnetic induction via the contactless communication connection, in particular using loosely coupled coils.

The device can be set up to generate electrical energy based on the contactless communication connection. In particular, a current can be induced in the device by the mobile device, in particular via the contactless communication connection. A current can be induced in the device through the contactless communication connection.

The device may include a passive transponder or a passive tag. As well the device may be a passive transponder or a passive tag.

The device cannot include any (own) energy supply. In particular, the device does not include a battery and/or a rechargeable battery. The device cannot be supplied with power or electrical energy without the contactless communication link. In other words, if the contactless communication link does not exist, no power or electrical energy may be available to the device. If the contactless communication link exists, power or electrical energy may be available to the device.

The private record may include a private key (also referred to as a private key), or be a private key, or represent a private key. In particular, the private key is a 256-bit number. The private key can interact with a public key (also known as a public key) to carry out a transaction. The public key can be derived from the private key. An address can be derived from the public key.

The private data set may include or be a seed phrase or represent a seed phrase. The seed phrase can also be called a seed, seed recovery phrase or backup seed phrase. Specifically, the seed phrase is a list of words. In particular, the seed phrase contains up to 30 words. The seed phrase preferably consists of 12 words or 24 words. A private key and/or a public key can be derived from the seed phrase. The seed phrase can interact with a public key to complete a transaction. A private key can preferably be derived from the seed phrase, whereby the private key can interact with a public key in order to carry out a transaction.

Preferably, the private data set cannot be derived from another data set. In particular, the private data set cannot be derived from a public key and/or an address.

The private record can be a private record for a transaction. A transaction may be feasible using the private record. The transaction may be a cryptocurrency transaction. In particular, the private data record is used to authorize and/or initiate a transaction, e.g. a cryptocurrency transaction. The transaction may be a receiving and/or sending of cryptocurrency. Cryptocurrency can be sent to an address and/or received at an address. The cryptocurrency can be Bitcoin or another cryptocurrency.

The private data set may be generated by or from the mobile device. Preferably, the private data set can be generated based on a user's input into the mobile device. In particular, the mobile device, for example a processor of the mobile device, is set up to generate the private data record and a public key. The generated private data set and/or the generated public key can be transmitted to the device, in particular transmitted to the device via the contactless communication connection. The generated and transmitted private data set and/or the generated and transmitted public key may be stored in the memory of the device. If the private data set and/or the public key are stored in the device, the contactless communication connection can be terminated or aborted.

Alternatively, the private data set and/or the public key can be generated outside the mobile device, for example by a server. The private record and/or the public key can be transmitted to the mobile device. The private data set and/or the public key may be transmitted from the mobile device to the device. The private record and/or the public key may be stored in the device's memory.

Preferably, the mobile device is not connected to the Internet when the private data record and/or the public key are generated by the mobile device. Alternatively or additionally, the mobile device may not be connected to the Internet when the private record and/or public key are transmitted from the mobile device to the device. Alternatively or additionally, the mobile device may not be connected to a cellular network when the private record and/or public key are generated by the mobile device. Alternatively or additionally, the mobile device may not be connected to a cellular network when the private data set and/or the public key are transmitted from the mobile device to the device.

A system is revealed. The system includes a device and a mobile device. The device includes a memory and an antenna for a contactless communication connection. The mobile device includes an antenna for a contactless communication connection. The device and the mobile device are set up, one to establish a contactless communication connection between the device and the mobile device. The mobile device is set up to transmit a private data set to the device via the contactless communication connection. The device is set up to store the private data set in the memory.

The device may be any device disclosed herein. Alternatively or additionally, the mobile device may be any mobile device disclosed herein. Alternatively or additionally, the contactless communication link may be any contactless communication link disclosed herein. Alternatively or additionally, the private record may be any private record disclosed herein.

In particular, the mobile device is set up to transmit the private data record to the device via the contactless communication connection.

The mobile device can be set up to generate the private data set. The mobile device is preferably set up to generate the private data record and an associated public key. The mobile device can be set up to transmit at least the generated private data set to the device. The device can be set up to store at least the private data set transmitted by the mobile device in the memory.

The mobile device may be configured to receive user input. The user input can be recognized or caused, for example, by touching a display on the mobile device. Based on the user input, the private data set and/or the public key may be generated by the mobile device. Based on the user input or based on further user input, the private data set and/or the public key can be transmitted from the mobile device to the device.

The antenna of the device may be a near field communication (NFC) antenna. Alternatively or additionally, the mobile device's antenna may be a near field communication (NFC) antenna.

For the contactless communication connection, the antenna of the device and the antenna of the mobile device can be inductively coupled.

A device is disclosed. The device includes a processor, a memory and an antenna. The antenna is set up to establish a contactless communication connection with a mobile device and to receive a private data set from the mobile device. The device, in particular the processor of the device, is set up to store the private data record in the memory.

The device may be any device disclosed herein. Alternatively or additionally, the mobile device may be any mobile device disclosed herein. Alternatively or additionally, the contactless communication link may be any contactless communication link disclosed herein. Alternatively or additionally, the private record may be any private record disclosed herein.

The contactless communication connection may be a contactless near field communication (NFC) connection.

A mobile device is revealed. The mobile device includes a processor and an antenna. The processor is set up to create or receive a private data set. The antenna is set up to establish a contactless communication connection with a device and to transmit the private data record to the device.

The mobile device may be any mobile device disclosed herein. Alternatively or additionally, the device may be any device disclosed herein. Alternatively or additionally, the contactless communication link may be any contactless communication link disclosed herein. Alternatively or additionally, the private record may be any private record disclosed herein.

The contactless communication connection may be a contactless near field communication (NFC) connection.

Disclosed is a method for carrying out a transaction. The method includes establishing a contactless communication connection between a device and a mobile device. The device includes a memory. A private data set is stored in the memory. The method includes transmitting the private data set from the device to the mobile device via the contactless communication link. The method includes performing the transaction using the private record.

The device may be any device disclosed herein. Alternatively or additionally, the mobile device may be any mobile device disclosed herein. Alternatively or additionally, the contactless communication link may be any contactless communication link disclosed herein. Alternatively or additionally, the private record may be any private record disclosed herein.

The contactless communication connection may be a contactless near field communication (NFC) connection.

The transaction may be a cryptocurrency transaction. The transaction can be a receiving and/or sending currency, in particular cryptocurrency.

What is disclosed is a computer program product. The computer program product includes instructions that, when the program is executed by a computer, cause the computer to perform a method disclosed herein. The method may be any method disclosed herein.

What is disclosed is a computer program product. The computer program product includes instructions that, upon execution of the program by a computer, cause a device and/or a mobile device to perform a method disclosed herein. The method may be any method disclosed herein.

Short description of the characters

• 1 schematisch ein System 1000;
• 2 schematisch ein Verfahren zum Speichern eines privaten Datensatzes; und
• 3 schematisch ein Verfahren zum Durchführen einer Transaktion.

The disclosure or further embodiments and advantages of the disclosure are explained in more detail below using figures, with the figures only describing exemplary embodiments of the disclosure. The same components in the figures are given the same reference numbers. Shown in the figures:

• 1 schematically a system 1000;
• 2 schematically a method for storing a private data set; and
• 3 schematically a procedure for carrying out a transaction.

Detailed description

1 shows a system 1000. The system 1000 includes a device 100 and a mobile device 200. In 1 The device 100 and the mobile device 200 are shown together, although the device 100 and the mobile device 200 are also described individually below and are also disclosed individually. That is, the device 100 can be present individually and the mobile device 200 can be present individually.

The device 100 may include a processor 110. Processes in the device 100 can be executed and/or controlled by the processor 110. The processor 100 may be a microprocessor.

The device 100 may include a memory 120. Memory 120 may be non-volatile memory. The storage capacity of the memory 120 can be less than 1 MB, preferably less than 200 kB, more preferably less than 500 B, more preferably less than 200 B.

The device 100 may include an antenna 130. The antenna 130 can be set up to establish a connection, in particular a contactless communication connection. The antenna may be a near field communication link (NFC) antenna. The device 100 can receive and/or send data via the antenna 130.

The device 100 may include an NFC chip. The NFC chip may include the processor 110 and the memory 120. The NFC chip preferably includes the antenna 130 or the NFC chip is connected to the antenna 130.

The device 100 may be a chip card, a key card, a smart card or an integrated circuit card (ICC). The device 100 is preferably a smart card.

The mobile device 200 may include a processor 210. The processor 210 can execute and/or control processes in the mobile device 200.

The mobile device 200 may include a memory 220. Memory 220 may be volatile or non-volatile memory. The memory 220 may also include volatile memory and non-volatile memory.

At least one application may be stored in the memory 220 of the mobile device 200. The application can be executed by the processor 210.

The mobile device 200 may include an antenna 230. The antenna 230 can be set up to establish a connection, in particular a contactless communication connection. The antenna 230 may be a near field communication link (NFC) antenna. The mobile device 200 can receive and/or send data via the antenna 230.

The mobile device 200 may include an interface 240. A user can make an entry into the mobile device 200 via the interface 240. For example, the interface 240 is a touch display (also referred to as a touch-sensitive display). When a user touches the touch display, the user can make an entry. The interface 240 can also connect an input device to the mobile device 200. The input device can be a mouse, a Include a keyboard, a speaker and/or a camera.

The mobile device 200 may include a power supply device 250. The power supply device 250 can provide electrical energy for the mobile device 200. The electrical energy can be used to operate the mobile device 200.

The mobile device 200 is preferably a smartphone, a smartwatch, a wearable device or a tablet.

A contactless communication connection can be established between the device 100 and the mobile device 200. The contactless communication connection is in particular an NFC connection. The contactless communication connection can be established between the antenna 130 of the device 100 and the antenna 230 of the mobile device 200.

Data can be transmitted from the mobile device 200 to the device 100 via the contactless communication connection. Data can also be transmitted from the device 100 to the mobile device 200 via the contactless communication connection.

The antenna 130 of the device 100 and the antenna 230 of the mobile device 200 may be inductively coupled. The device 100 can be supplied with electrical energy by the mobile device 200 if the device 100 and the mobile device 200 are connected to one another in a contactless manner. In particular, the device 100 does not include its own power supply, for example no battery and/or rechargeable battery of its own. If the device 100 and the mobile device 200 are not connected to one another in a contactless manner, the device 100 may not have any electrical energy available.

The connection between the device 100 and the mobile device 200 may be initiated or triggered by user input. For example, a user can make an input into the mobile device 200 via the interface 240 of the mobile device 200. Based on the input, a connection between the device 100 and the mobile device 200 can be established.

The mobile device 200 may be configured to create or generate a private data set. The private data set is preferably a private key or a seed phrase. The private record may be a private record for one or more transactions, for example one or more cryptocurrency transactions. This means that the private data set can be used for several, e.g. more than two or more than ten, transactions, in particular cryptocurrency transactions.

The mobile device 200 may be configured to create or generate a pair of a private data set and a public data set, for example a public key.

The private data set and/or the public key may be transmitted to the device 100 via the contactless communication link between the device 100 and the mobile device 200. The private data set and/or the public key can be stored in the device 100, in particular in the memory 120 of the device 100.

The generation of the private data set and/or the public key can be initiated or triggered by user input. For example, a user can make an input into the mobile device 200 via the interface 240 of the mobile device 200. Based on the input, generation of the private data set and/or the public key can be initiated or triggered.

The transmission of the private data set and/or the public key can be initiated or triggered by user input. For example, a user can make an input into the mobile device 200 via the interface 240 of the mobile device 200. Based on the input, a transmission of the private data set and/or the public key from the mobile device 200 to the device 100 can be initiated or triggered.

2 shows schematically a sequence of a method for storing a private data set.

A contactless communication connection can be established between a device 100 and a mobile device 200. Device 100 may be any device 100 disclosed herein. Mobile device 200 may be any mobile device 200 disclosed herein. The contactless communication link may be any contactless communication link disclosed herein.

The mobile device 200 can create a private record. Likewise, the mobile device 200 may generate a pair of a private record and a public record, such as a public key. The private data set and/or the public data set can be created (in time) before the ver binding between the device 100 and the mobile device 200. Alternatively, the private data set and/or the public data set can be generated (in time) after the connection between the device 100 and the mobile device 200 has been established.

The private data set and/or the public data set may be transmitted from the mobile device 200 to the device 100. The transmission can take place via the contactless communication connection. The contactless communication connection can be an NFC connection.

The private data set and/or the public data set can be stored in the device 100, in particular in the memory 120 of the device 100.

The contactless communication connection between the device 100 and the mobile device 200 can be terminated or aborted. In particular, the contactless communication connection between the device 100 and the mobile device 200 is terminated or aborted after the private data set and/or the public data set are or have been saved in the device 100.

After the contactless communication connection between the device 100 and the mobile device 200 has been terminated, the device 100 may no longer be supplied with electrical energy. Electrical energy for operating the device 100 may have been provided by the contactless communication link.

The private data set and/or the public data set may be stored offline in the device 100. The device 100 can be cold storage.

3 shows schematically the flow of a transaction. The transaction may involve a device 100 disclosed herein. Alternatively or additionally, the transaction may involve a mobile device 200 disclosed herein.

A device 100 may have a private data set and/or a public data set stored, for example in the memory 120 of the device 100. The private data set and/or the public data set may have been stored in the device 100 by a method disclosed herein.

A contactless communication connection can be established between the device 100 and the mobile device 200, for example an NFC connection.

The private data set and/or the public data set may be transmitted from the device 100 to the mobile device 200.

The mobile device 200 may use the private record and/or the public record to perform a transaction. The transaction may be a cryptocurrency transaction.

After transmitting the private data set and/or the public data set from the device 100 to the mobile device 200, the contactless communication connection can be terminated. Likewise, the contactless communication connection can be terminated after the transaction has been carried out.

The connection between the device 100 and the mobile device 200 can be initiated or established based on a user input into the mobile device 200. That is, a contactless communication connection between the device 100 and the mobile device 200 can be established when a user makes an input into the mobile device 200.

The transfer of the private data set and/or the public data set from the device 100 to the mobile device 200 may be initiated or triggered based on a user input into the mobile device 200. That is, a transfer of the private data set and/or the public data set from the device 100 to the mobile device 200 can be carried out when a user makes an entry into the mobile device 200.

The transaction may be initiated or triggered based on a user input into the mobile device 200. That is, a transaction can be carried out when a user makes an entry into the mobile device 200.

List of reference symbols:

100

contraption

110

processor

120

Storage

130

antenna

200

Mobile device

210

processor

220

Storage

230

antenna

240

interface

250

Energy supply facility

1000

system

Claims (10)

Procedure for saving a private record, the procedure with the steps: - Establishing a contactless communication connection between a device (100) and a mobile device (200), the device (100) comprising a memory (120); - Creating the private data set; - Transmitting the private data set from the mobile device (200) to the device (100); and - Storing the private data set in the memory (120) of the device. Procedure according to Claim 1 , wherein the contactless communication link is a near field communication link; and/or wherein the contactless communication connection cannot be established if a distance between the device (100) and the mobile device (200) is greater than 0.50 m, in particular greater than 0.15 m. Method according to one of the preceding claims, wherein the device (100) is set up to generate electrical energy based on the contactless communication connection; and/or wherein the device (100) comprises a passive transponder; and/or wherein the device (100) is a chip card. Method according to one of the preceding claims, wherein the private data set comprises a private key or is a private key; and/or wherein the private data set comprises or is a seed phrase; and/or wherein the private data record is a private data record for a transaction, in particular for a cryptocurrency transaction. Method according to one of the preceding claims, wherein the private data record is generated by the mobile device (200), in particular based on an input from a user into the mobile device (200). System (1000) comprising a device (100) and a mobile device (200), wherein: - the device (100) comprises a memory (120) and an antenna (130) for a contactless communication connection; - the mobile device (200) comprises an antenna (230) for a contactless communication connection; and - the device (100) and the mobile device (200) are set up to establish a contactless communication connection between the device (100) and the mobile device (200), the mobile device (200) is set up to send a private data set to the device via the contactless communication connection (100), and the device (100) is set up to store the private data set in the memory (120). System (1000) after Claim 6 , wherein the antenna (130) of the device (100) is a near field communications antenna; and/or wherein the antenna (230) of the mobile device (200) is a near-field communication antenna. Device (100) with a processor (110), a memory (120) and an antenna (130), wherein: - the antenna (130) is set up to establish a contactless communication connection, in particular a contactless near-field communication connection, with a mobile device (200) and to receive a private data set from the mobile device (200); and - The processor (110) is set up to store the private data record in the memory (120). Mobile device (200) with a processor (210) and an antenna (230), wherein: - the processor (110) is set up to create a private data record; and - The antenna (230) is set up to establish a contactless communication connection, in particular a contactless near-field communication connection, with a device (100) and to transmit the private data record to the device (100). Procedure for conducting a transaction, the procedure with the steps: - Establishing a contactless communication connection, in particular a contactless near-field communication connection, between a device (100) and a mobile device (200), the device (100) comprising a memory (120) and a private data set being stored in the memory (120); - Transmitting the private data set from the device (100) to the mobile device (200) via the contactless communication link; and - Conducting the transaction, especially a cryptocurrency transaction, using the private record.

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